Present day implantation of artificial materials that contact blood is a frequent medical occurrence despite the paucity of knowledge concerning the biochemical and biophysical interactions of foreign surfaces with blood. The development of prosthetic devices which must contact blood is limited by the reactions which promote thrombogenesis. The platelet -- a major blood reactant activated by any non-endothelial surface -- may be retained or returned to the circulation in an altered state. During this process, the platelet may accelerate coagulation factor activation and promote thrombosis. None of these altered platelet states is desirable. There is a considerable amount of evidence to suggest that platelet and coagulation factor activation can be modified by fatty acids in their environment. We propose to determine which of the fatty acids contained within albumin and absorbed to a foreign surface can minimize platelet activation. Ex-vivo shunts of polyvinylchloride and polyurethane will be placed in goats and fibrinogen and platelet turnover studies done. The shunt will be pre-treated with goat albumin modified to contain different fatty acids. These data are expected to tell us how we can pretreat any device made of different polymers to optimize thromboresistance.